Abstract
Thermally reduced graphene oxide (TRGO) is a graphene-based nanomaterial that has been identified as promising for the development of amperometric biosensors. Urease, in combination with TRGO, allowed us to create a mediator-free amperometric biosensor with the intention of precise detection of urea in clinical trials. Beyond simplicity of the technology, the biosensor exhibited high sensitivity (2.3 ± 0.1 µA cm−2 mM−1), great operational and storage stabilities (up to seven months), and appropriate reproducibility (relative standard deviation (RSD) about 2%). The analytical recovery of the TRGO-based biosensor in urine of 101 ÷ 104% with RSD of 1.2 ÷ 1.7% and in blood of 92.7 ÷ 96.4%, RSD of 1.0 ÷ 2.5%, confirmed that the biosensor is acceptable and reliable. These properties allowed us to apply the biosensor in the monitoring of urea levels in samples of urine, blood, and spent dialysate collected during hemodialysis. Accuracy of the biosensor was validated by good correlation (R = 0.9898 and R = 0.9982) for dialysate and blood, utilizing approved methods. The advantages of the proposed biosensing technology could benefit the development of point-of-care and non-invasive medical instruments.
Highlights
According to a review on biosensing technologies, the use of biosensors for medical technologies has increased exponentially [1]
The prototype amperometric urea biosensor was constructed by coupling an enzymatic membrane consisting of urease and synthesized carbonaceous nanomaterials with the graphite electrode surface
Thermally reduced graphene oxide (TRGO)-based electrodes, since the thermal reduction procedure leads detection of such pH changes, we proposed TRGO‐based electrodes, since the thermal reduction to the formation oxygen groups procedure leadsoftospecific the formation of specific oxygen groupslactone, are of takingon part protonoftransfer the surface of TRGO [24]
Summary
According to a review on biosensing technologies, the use of biosensors for medical technologies has increased exponentially [1]. Since urea level and fluctuation is one of the most important indicators of possible kidney and liver dysfunction, earliest possible detection and real-time monitoring of this metabolite in human body fluids, such as urine or blood, occupies a significant place in clinical biochemistry [2,3,4]. According to a recent report, blood urea nitrogen (BUN) is the most valuable independent risk factor to predict severe acute pancreatitis (AP) [6]. BUN tests in medical diagnostics have become the most commonly used method to evaluate blood urea levels. The use of alternative methods examining urea in body fluids other than blood have great potential [4]. With regard to non-invasive technologies, Sensors 2020, 20, 4496; doi:10.3390/s20164496 www.mdpi.com/journal/sensors
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